1. Field of the Invention
The present invention relates to a handsaw that can be folded into a handle (hereinafter referred to as a xe2x80x9cfolding sawxe2x80x9d). In more particular, the present invention relates to a saw in which the blade is pivotally attached by its base end to the top end of a handle having a U-shaped cross section and can be revolved to-be folded-into the handle when not in use so as to be used as a pruning saw, a gardening saw or as a crafting saw.
2. Prior Art
A conventional folding saw has a straight blade pivotally attached by its base end to the top end of a straight handle. When the blade is folded into the handle, the edge is completely housed within the handle. Recently, however, as shown in FIGS. 15(a) and 15(b) saws having a concavely curved blade A and a concavely curved edge B have come into widespread use for pruning trees. Such saws having a concavely curved blade edge are generally called curved saws. Compared with a conventional saw with a straight blade, a curved saw is less likely to disengage from the object of cutting, so it is easier to cut the object using such a saw.
Accordingly, a folding saw having a concavely curved edge B housed in handle C which is also concave in the same direction as the edge B as shown in FIGS. 15(a) and 15(b) has been developed. Other variations of the folding saw include those having a concave edge and a straight handle and those combining a straight edge with a concave handle.
A folding saw combining a concavely curved edge and a straight handle has a mildly curved form when unfolded as shown in FIG. 15(a). When the blade is folded, however, a portion of the edge, in particular, the middle portion of the curved edge, is exposed as shown in FIG. 15(b). This is dangerous because this exposed portion E can injure a finger or damage an object while the folding saw is being carried or stored. The edge itself can also be damaged by another object that accidentally comes into contact with it.
The object of the present invention is to provide a handsaw that can overcome these defects inherent in the conventional saws by protecting the exposed edge part of the blade with a protective cover.
To achieve the object mentioned above, the present invention includes a protective cover which can be pulled out or pushed into the housing groove of the handle for housing the blade. When the blade is folded, the protective cover housed in the housing groove is pushed out of the housing groove so as to cover the edge of the blade exposed from the housing groove of the handle.
In order to allow the protecting cover covering the edge of the blade to project out of the housing groove, the protective cover is pivotally supported by a pivot which is inside the housing groove and is located near the end of the handle. The protective cover can be revolved around the pivot so as to be retracted into the housing groove. In this condition, the protective cover is energized by a first spring so that it is constantly pushed into the housing groove, and when the top end of the folded blade pushes a portion of the protective cover between the pivot and the bottom end of the handle, the protective cover pivotally projects out of the housing groove, against the resiliency of the first spring. In this way, when the blade is folded, the protective cover covers the blade, and when the blade is unfolded into a ready-to-cut condition, the protective cover is housed inside the housing groove.
At this time, at the top end of the handle at the point where the blade is pivotally attached, a stopper is preferably provided so that the blade is stopped at the working position at which the blade is fully open for cutting objects and at the folding position at which the blade is fully folded, and that the protective cover forcibly holds the blade at the housed position at which the blade is folded, against the resiliency of the first spring. More specifically, when the blade is opened slightly, the edge becomes exposed from the housing groove accordingly, and at the same time, the protective cover moves towards the housing groove, causing the edge to be further exposed. To prevent this, the stopper that stops the blade at its folded and housed position is provided so that the blade does not open unintentionally while it is being carried.
The protective cover which revolves around the pivot at the bottom end of the handle may be designed so that it can be pulled out of or pushed into the housing groove by means of the force of a second spring positioned between the pivot and the middle of the handle. Instead of using the spring to allow the protective cover to retract or emerge, the protective cover may be provided with an opener that sticks out of the handle, so that the opener can be operated by a finger so as to retract the protective cover into or emerge from the housing groove.
FIG. 1 is a longitudinal section view of an embodiment of a folding saw according to the present invention with its bladed folded;
FIG. 2 is a longitudinal section view of the same folding saw as in FIG. 1 with its blade slightly unfolded;
FIG. 3 is a longitudinal section view of the same folding saw as in FIG. 1 with its blade completely unfolded;
FIG. 4 is a cross sectional view taken along the line IVxe2x80x94IV of FIG. 1;
FIG. 5 is a semi cross sectional perspective view showing only the protective cover of the folding saw shown in FIG. 1;
FIGS. 6(a) and 6(b) are partially cut front views of a folding saw in another embodiment;
FIGS. 7(a) and 7(b) are partially cut front views of a folding saw in yet another embodiment;
FIG. 8 is a partially cut front view of a folding saw with its blade completely unfolded in yet another embodiment;
FIG. 9 is a front view of the protective cover of the embodiment shown in FIG. 8;
FIG. 10 is a plan view of the protective cover of the embodiment shown in FIG. 8;
FIG. 11 is a cross sectional view taken along the line XIxe2x80x94XI of FIG. 9;
FIGS. 12(a) and 12(b) are cross sectional views taken along the line XIIxe2x80x94XII of FIG. 8, of which FIG. 12(a) shows the condition in which the edge is protected; and FIG. 12(b) shows the condition in which the handle is grasped together with the protective cover after unfolding the blade;
FIG. 13 is a front view of the folding saw shown in FIG. 8 with its blade folded;
FIG. 14 is a longitudinal section view of a folding saw in yet another embodiment, showing a portion of the handle housing the protective cover; and
FIGS. 15(a) and 15(b) are front views of an example of a conventional folding saw.